Adult patients with ESRD starting PD as their first renal replacement therapy modality will be studied. Patients will be recruited 1-3 weeks prior to starting PD treatment. At baseline, specific studies for microneurography (MSNA), fasting plasma insulin, leptin, catecholamines and brain natriuretic peptide (BNP) will be performed. EKG will be recorded and digitized for further assessment of heart rate variability using power spectral analysis. Extracellular fluid volume status will be assessed by bioelectrical impedance. Central vascular volume will be assessed from inferior vena cava (IVC) by heart ultrasound. Consequently 24-h ambulatory blood pressure monitoring(ABPM)and a 24-h urine collection for urea clearance and creatinine clearance will be done.